DELETE clause
The DELETE clause is used to delete nodes and edges from the database.
Data Set
The following examples are executed with this data set. You can create this data set locally by executing the queries at the end of the page: Data Set.
1. Deleting a node
The DELETE clause can be used to delete a node.
MATCH (c:Country { name: 'United Kingdom' })
DELETE c;
Output:
Failed to remove node because of it's existing connections. Consider using DETACH DELETE.
This will however result in an error because DELETE can only be used on nodes that have no relationships.
2. Deleting a node and its relationships
The DELETE clause can be used to delete a node along with all of its relationships with the keyword DETACH.
MATCH (n:Country { name: 'United Kingdom' })
DETACH DELETE n;
Output:
Empty set (0.001 sec)
3. Deleting a relationship
The DELETE clause can be used to delete a relationship.
MATCH (n:Country { name: 'Germany' })-[r:LIVING_IN]-()
DELETE r;
Output:
Empty set (0.003 sec)
4. Deleting everything
To delete all nodes and relationships in a graph, use the following query.
MATCH (n)
DETACH DELETE n;
Output:
Empty set (0.001 sec)
Data set Queries
We encourage you to try out the examples by yourself. You can get our data set locally by executing the following query block.
MATCH (n) DETACH DELETE n;
CREATE (c1:Country { name: 'Germany', language: 'German', continent: 'Europe', population: 83000000 });
CREATE (c2:Country { name: 'France', language: 'French', continent: 'Europe', population: 67000000 });
CREATE (c3:Country { name: 'United Kingdom', language: 'English', continent: 'Europe', population: 66000000 });
MATCH (c1),(c2)
WHERE c1.name= 'Germany' AND c2.name = 'France'
CREATE (c2)<-[:WORKING_IN { date_of_start: 2014 }]-(p:Person { name: 'John' })-[:LIVING_IN { date_of_start: 2014 }]->(c1);
MATCH (c)
WHERE c.name= 'United Kingdom'
CREATE (c)<-[:WORKING_IN { date_of_start: 2014 }]-(p:Person { name: 'Harry' })-[:LIVING_IN { date_of_start: 2013 }]->(c);
MATCH (p1),(p2)
WHERE p1.name = 'John' AND p2.name = 'Harry'
CREATE (p1)-[:FRIENDS_WITH { date_of_start: 2011 }]->(p2);
MATCH (p1),(p2)
WHERE p1.name = 'John' AND p2.name = 'Harry'
CREATE (p1)<-[:FRIENDS_WITH { date_of_start: 2012 }]-(:Person { name: 'Anna' })-[:FRIENDS_WITH { date_of_start: 2014 }]->(p2);
MATCH (p),(c1),(c2)
WHERE p.name = 'Anna' AND c1.name = 'United Kingdom' AND c2.name = 'Germany'
CREATE (c2)<-[:LIVING_IN { date_of_start: 2014 }]-(p)-[:LIVING_IN { date_of_start: 2014 }]->(c1);
MATCH (n)-[r]->(m) RETURN n,r,m;